Mechanical Refrigeration with Independent Engine or Electric Motor:
The mechanical-refrigeration system mounted at the vehicle contains an independent engine. Some are also equipped having an electric motor for stand-by operation at the charging station. These units are obtainable in two ranges:
(1) 5.86 to 10.3 kW capacity at 1.5°C.
(2) 1.76 to 5.28 kW capacity at - 18°C in a 40°C environment.
Mechanical Refrigeration Deriving Power from Vehicle Engine or Transmission
There are several practical designs obtainable. The refrigeration compressor might be either coupled directly to the engine, or might take off the power by transmission. In one of design, the engine runs an alternator. The A.C. current is rectified & it is utilized to run D.C. motors for compressor & fans. However, the refrigeration is produced just while the vehicle engine is in operation.